ASTM International recently approved ethanol as a feedstock in ASTM D7566 Annex A5, the Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons for alcohol-to-jet synthetic paraffinic kerosene (ATJ-SPK). The revision of ASTM D7566 Annex A5 to increase the blend ratio of ATJ-SPK to 50% was also completed. Companies such as Lanzatech (earlier post) and Byogy (earlier post), both of which have been working for years on the approval process, stand to benefit from the decision.

Following a review by the OEMs and the Federal Aviation Administration (FAA) that the ethanol-derived ATJ-SPK was fit for purpose for use on aircraft and engines, an ASTM Subcommittee D02.J on Aviation Fuel ballot was submitted to the ASTM membership for review (the “D02.J Ballot”).

The fit-for-purpose determination was based on a Research Report led by LanzaTech and submitted to ASTM which contained detailed data measured on ethanol-based ATJ produced using the technology originally developed by the Pacific Northwest National Lab (PNNL) and scaled up by LanzaTech. The Research Report demonstrated that the LanzaTech-PNNL ATJ-SPK meets all fit-for-purpose properties required by ASTM D4054, the Standard Practice for Qualification and Approval of New Aviation Turbine Fuels and Fuel Additives, including when blended at the 50% level with conventional jet.

Top: Lanzatech uses a proprietary microbe to ferment CO-rich gases to ethanol. Bottom: The ethanol is then taken through a four-step process of dehydration, oligomerization, hydrogenation and fractionation to produce jet-range hydrocarbons. Click to enlarge.

ASTM International will publish the revision of ASTM D7566 on its website in the coming months.

Earlier this year, LanzaTech and PNNL passed the US Department of Energy (DOE) contracted independent engineering validation for both gas-to-ethanol and ethanol-to-jet technologies, as part of a low carbon jet and diesel design and engineering project co-funded by the DOE’s Bioenergy Technologies Office under the Project Development for Pilot and Demonstration Scale Manufacturing of Biofuels, Bioproducts and Biopower (PD2B3) program.

LanzaTech is now preparing a design and engineering package for an ATJ production facility implementing the LanzaTech-PNNL ethanol based ATJ-SPK pathway now accepted under ASTM D7566. The design will be for a facility that can produce 3 million gallons per year of ATJ blendstock and diesel using sustainable ethanol feedstocks from LanzaTech’s gas fermentation, which uses feedstocks such as industrial off gas, biomass wastes and residues, and unsorted, unrecyclable municipal solid waste, as well as ethanol from other sustainable sources.

Because ethanol-based ATJ-SPK can use ethanol produced from any feedstock, using any conversion technology, approval of ethanol in ASTM D7566 Annex A5, means that sustainable aviation fuel can be produced anywhere around the globe, from available environmentally, economically, and socially sustainable feedstocks in each region.

At a DOE-sponsored Alternative Aviation Fuel Workshop in 2017, Dr. Jeongwoo Han of Argonne National Laboratory reported that analysis showed that lignocellulosic ethanol-to-jet (ETJ) via corn stover had the potential to reduce greenhouse gas emissions by 73% relative to fossil feedstocks. Starch ethanol showed a lower impact on the GHG reduction relative to fossil feedstocks (around 10%). Further sustainability metrics, including water usage, were a major driver for ethanol production.

For the sugar-to-jet (STJ) routes, which considered both biological and catalytic conversion to ATJ from lignocellulosic feedstocks, the source of hydrogen (either fossil-derived or biomass-derived) can impact the GHG estimates. While biomass-derived hydrogen significantly reduces the GHG emissions for the pathway, it comes at both a yield and economic cost. However, fossil-derived hydrogen may not help meet specific GHG targets for the pathway. Additionally, co-product handling influences the final results for the LCA, but the impact is much lower when the co-product is fuel rather than a commodity chemical.

LanzaTech’s ethanol-based ATJ-SPK will be eligible for use as a blending component with standard Jet A/Jet A1 for commercial airline use in the United States and in most countries around the globe. Under the revised ASTM D7566 LanzaTech ATJ-SPK will be eligible to be used up to a 50% blend in conventional jet fuel for commercial flights.

Comments

(dafuq? where my comment go?)

This fermentation scheme is a waste of time and energy. Syngas can be converted directly to methanol over a copper catalyst; this eliminates both the energy losses in fermentation and the energy cost of distillation. Then Mobil ZSM-5 catalyst converts methanol to ethylene:

2 CH3OH -> C2H4 + 2 H2O

Both steps are energetically "downhill", so no further energy input is required. Convert to jet fuel from there.